This invention relates to surface processing of a power transmission component and, more particularly, to methods of surface processing that minimize dimensional alteration and the identification of alloys that possess properties and microstructures conducive to surface processing in such a way that the processed alloy possesses desirable surface and core properties that render it particularly effective in applications that demand superior properties such as power transmission components. Absent the combination of alloy selection and processing that are taught herein, such superior properties would be unavailable.
For iron-based metal alloy components, such as power transmission components, it is often desirable to form a hardened surface case around the core of the component to enhance component performance. The hardened surface case provides wear and corrosion resistance while the core provides toughness and impact resistance.
There are various conventional methods for forming a hardened surface case on a power transmission component fabricated from a steel alloy. One conventional method, nitriding, utilizes gas, salt bath or plasma processing. The nitriding process introduces nitrogen to the surface of the component at an elevated temperature. The nitrogen reacts with the steel alloy to form the hardened surface case while the core of the component may retain the original hardness, strength, and toughness characteristics of the steel alloy. This conventional process provides a hardened surface case, however, the elevated temperatures of the nitriding process may over-temper the core and diminish its properties and/or induce dimensional distortion of the component such that additional grinding or dimensionalizing steps are required to bring the component into dimensional tolerance.
Accordingly, it is desirable to identify a particular alloy for a surface processing method that minimizes dimensional alteration of a power transmission component and essentially eliminates dimensionalizing processes subsequent to the case hardening process.